The present invention relates to a PPP terminating equipment, and a network equipment, such as a router, and the like, in particular to the PPP terminating equipment and the network equipment both capable of rapidly processing a response to an LCP echo requirement, and a method of responding to the LCP echo requirement.
Conventionally, a PPP (Point-to-Point Protocol) terminating equipment has been mainly used, when a network equipment, such as a router, and the like is connected by the use of a PPP link.
Numbers of the PPP link terminals required for the PPP terminating equipment correspond to numbers of lines by 1 to 1 in a case of a non-multiple interface, such as POS (Packet over SONET), or the like. On the other hand, the PPP link can be established per each VPI/VCI (virtual path identifier/virtual channel identifier) or per each channel, in a case that a multiple interface, such as ATM (Asynchronous Transfer Mode), a channelized interface, or the like is contained. As a result, it becomes necessary that several thousands to several ten thousands number of the PPP links can be terminated by a single PPP terminating equipment.
Processing required for the PPP terminating equipment are divided into two major processing, namely, a processing of establishing a link and a processing of maintaining the link. The former, namely, the processing of establishing the link is such a processing that negotiates with the object of the link and decides and admits parameters required for connection of PPP.
On the other hand, the latter, namely, the processing of maintaining the link is, for example, a processing of response to LCP (Link Control Protocol) echo requirement packet transmitted and received at intervals of several seconds to confirm normality of the link, mainly after the PPP link has been established. An equipment that transmitted the LCP echo requirement judges the link to be invalid and disconnects the link, if any responses were not received from the opposite PPP terminating equipment during a predetermined certain time. Consequently, if the LCP echo requirement has been received, the PPP terminating equipment must give a response to the LCP echo requirement during the predetermined certain time by all means. Herein, numbers of the received LCP echo requirements are increased, when numbers of the links are many. Accordingly, a processing of responding to the LCP echo requirement is a large load on a processor.
In a conventional technique, the above-mentioned processing of responding to the LCP echo requirement is processed mainly by the use of a general purpose microprocessor. However, load on the general purpose microprocessor is increased, as numbers of connection of PPP are increased. For example, in the above-mentioned processing of establishing a link, it takes a longer time to finish the connection of all the links. In addition, even if the link has been established, only the PPP links of numbers corresponding to numbers of the LCP echo requirements capable of being processed by the general purpose microprocessor can be maintained Thus, in the conventional technique, it is possible only to obtain the performance of processing far inferior to numbers of connection of PPP capable of being established in an actual multiple interface.